1. Field of the Invention
The present invention relates to a disposable diaper and further to a disposable diaper having a pattern sheet allowing a pattern printed thereon to be observed only at a portion of the back face or front face of the diaper, and a method for manufacturing the same.
2. Description of the Related Art
In either the so-called xe2x80x9copen typexe2x80x9d disposable diaper for infants or babies or a disposable diaper which is formed in advance into the underpants shape, it is customary that a pattern such as the image of an animal or character appears on the outer sheet of the diaper.
The conventional method for attaching the pattern is generally done by printing a film to form the outer sheet (or back sheet) of the diaper in advance with continuous patterns or repeated patterns and by manufacturing the diapers of the outer sheet continuously by an automatic machine.
In the disclosure of Japanese Patent Laid-Open No. H3-90602 (90602/1991), on the other hand, a see-through outer sheet (or back sheet) is used and is jointed to another member on the inner side through a hot-melt type adhesive having a color. This hot-melt type adhesive is applied in a dotted shape to form a highly dense region of dots for expressing such an image or pattern as can be observed through the outer sheet.
The aforementioned method for manufacturing the diaper by using the film printed in advance with the pattern as the outer sheet is accompanied by the step of laying an absorbent layer and a liquid-permeable inner sheet (or top sheet) over the outer sheet having a band shape and by the subsequent step of separating individual diapers. This makes it substantially impossible for the completed disposable diaper to control what of its surface position the pattern or image is located at. It follows that the print on the outer sheet is limited to the continuous patterns or the repeated patterns, as described above, to restrict the degree of freedom for selecting the design of the pattern to appear on the surface. On the other hand, it is necessary to print the entire film for the outer sheet. This necessity raises the cost for manufacturing the outer sheet (or a film having the printed pattern). This cost is extremely raised if the pattern is to be expressed by the multicolor print, for example.
In the disclosure of Japanese Patent Laid-Open No. H3-90602 (90602/1991), moreover, a colored hot-melt type adhesive is applied to the outer sheet by using a roll coater to express the pattern by the dot application. This expression is unable not only to achieve a clear pattern but also to make a multicolor pattern. Moreover, although FIG. 1 of Japanese Patent Laid-Open No. H3-90602 (90602/1991) shows the pattern appearing only on one portion of the diaper, there arises a defect that a dislocation is liable to occur between the completed diaper and the pattern if the pattern is attached by the roll coater according to the aforementioned method.
The present invention has an object to provide a disposable diaper capable of attaching a pattern to only one portion of the diaper at a low cost and preventing any serious cost rise even where the pattern of a multicolor print is used, for example, and a method for manufacturing the disposable diaper.
According to the invention, there is provided a disposable diaper, comprising: an outer sheet facing outward; a liquid-permeable inner sheet facing a liquid receiving side; and an absorbent layer interposed between the outer sheet and the inner sheet, to form a front face portion to be applied to the abdomen of a wearer, an intermediate portion to be applied to the crotch, and a back face portion to be applied to the back side,
wherein a pattern sheet having a pattern and an area smaller than an area of the diaper, as viewed from the back face or the front face of the diaper, is adhered to the inner side of the outer sheet; and
wherein the outer sheet allows the pattern to be observed therethrough.
The disposable diaper of the invention may be the so-called xe2x80x9copen typexe2x80x9d or may be formed in advance into an underpants type.
The view of the disposable diaper, as taken from the back face or the front face, means that the diaper is flattened, while not being worn by a human body, to have its front face portion and back face portion in face-to-face contact with each other, and that this state is seen from the back side or the front side. Alternatively, the view means the projected shape taken from the back face or the front face by making the disposable diaper the same stereoscopic as it is worn by the human body. In short, it is sufficient to satisfy that the area to be occupied by the pattern sheet is smaller than the area (or the projected area) of the diaper either in the flattened state or in the stereoscopic state.
For example, it is preferred that the area to be occupied by the pattern sheet is 50% or less of the area of the diaper, as viewed from the back face or the front face of the diaper.
The pattern sheet may have any of polygonal, circular and elliptical shapes.
Preferably, the pattern sheet is an air- and moisture-permeable sheet on the surface of which the pattern is printed.
When the pattern sheet is exemplified by the air- and moisture-permeable sheet, as specified above, and when the outer sheet is also air- and moisture-permeable, the air- and moisture-permeating functions of the outer sheet are not obstructed by the pattern sheet adhered thereto. When the pattern sheet is so small as to have 50% or less of the area of the outer sheet, as viewed from the back face or the front face of the diaper, however, those functions of the outer sheet are hardly influenced and the entire diaper is prevented from being steamed stuffy, even if the pattern sheet has no air -and moisture-permeability.
For example: the outer sheet may be made of a nonwoven fabric; a liquid-impermeable sheet or a hydrophobic sheet may be disposed inside of the outer sheet; and the pattern sheet may be adhered between the outer sheet and the liquid-impermeable sheet or the hydrophobic sheet.
Alternatively, the outer sheet may be made of a film, and the pattern sheet may be adhered to the inner face of the film.
According to the invention, on the other hand, there is provided a method for manufacturing a disposable diaper, comprising: an outer sheet facing outward; a liquid-permeable inner sheet facing a liquid receiving side; and an absorbent layer interposed between the outer sheet and the inner sheet, to form a front face portion to be applied to the abdomen of a wearer, an intermediate portion to be applied to the crotch, and a back face portion to be applied to the back side,
the method comprising:
(a) the step of adhering a pattern sheet having a pattern and a smaller area than an outer sheet to a predetermined position on the inner face of the outer sheet which can be seen through;
(b) the step of placing an absorbent layer on the inner side of the outer sheet; and
(c) the step of laminating an inner sheet on the inner side of the absorbent layer, so that the pattern of the pattern sheet having an area smaller than an area of the diaper, as viewed from the back face or the front face of the diaper, can be seen through the outer sheet.
In this case, between the step (a) and the step (b), there can be further comprised the step of laying a liquid-impermeable sheet or a hydrophobic sheet for covering the inner side of the outer sheet, and sandwiching the pattern sheet between the outer sheet and the liquid-impermeable sheet or the hydrophobic sheet.
If the precision at the time of adhering the pattern sheet to the outer sheet is retained, according to the manufacture method of the invention, the pattern can be attached to the predetermined position of the diaper without dislocation. It is also possible to easily match the changes in the position and the size of the pattern.